Introduction

Irritable Bowel Syndrome (IBS) is a complex gastrointestinal functional disorder characterized by abdominal pain or discomfort and altered bowel habits. Despite its prevalence, and often chronic relapsing nature, the underlying pathophysiology of IBS remains incompletely understood. The etiology is likely multifactorial. Chronic low-grade subclinical inflammation has been implicated in the disease process and thought to perpetuate the symptoms of IBS.
Through previous studies on the serum proteomic profiles of IBS patients, it was seen that some inflammatory proteins are overexpressed in IBS, giving rise to a different serum proteome signature in IBS compared to healthy controls. [1,2] Systemic inflammatory protein profiles have also been used to distinguish patients with ulcerative colitis from IBS patients. [3] This suggests that proteomic profiling can potentially give us more insight into understanding the inflammatory mechanisms driving IBS.

Aims & Methods

This study aims to determine if systemic inflammatory protein profiles differ between patients with IBS and healthy controls.
Serum inflammatory proteins from 42 asymptomatic healthy controls undergoing screening colonoscopy with no colonic pathology, and 41 IBS patients fulfilling ROME IV criteria were analyzed using the Olink Target 96 Inflammation Panel. A partial-least square discriminant analysis was undertaken to identify additional discriminative inflammatory proteins. Univariate t-test analyses, with false discovery rate correction, were also performed to identify proteins unique to varying subtypes of IBS.

Results

Among IBS patients, the mean age was 48.6 years (SD +/- 15.5), while 31.7% were male. Among the controls, the mean age was 61.6 years (SD +/- 7) and 50% were male. There were 18 (43.9%), 14 (34.1%), 8 (19.5%) and 1 (2.4%) IBS patients with IBS-D, IBS-M, IBS-C and IBS-U respectively. 73.2% of IBS patients and 90.5% of controls were Chinese, with the rest being Indians, Malays or others.
Majority of the proteins (n=88, 96%) were prevalent in >40% of the study participants. Of which, 6 proteins (AXIN1, CCL19, CCL28, CD8A, EN-RAGE, MMP10) were differentially abundant (p<0.05) in IBS patients. Participants with IBS-C displayed higher levels of CD8A, while participants with IBS-D showed higher levels of AXIN1 and EN-RAGE (Table 1).
Interestingly, a recent study showed that CCL28 is elevated in IBS patients, which is consistent with our findings. [4] EN-RAGE has also been studied to be elevated in several digestive diseases including IBS, inflammatory bowel disease, digestive tract cancers, necrotizing enterocolitis and gastroenteritis. [5]

Table 1: Differentially abundant immunoproteins in IBS

Conclusion

We conclude that the serum cytokine profiles of IBS patients differ from that of healthy controls. We identified 6 immunoproteins that distinguish IBS from controls, and found that the levels of these immunoproteins also differ amongst the IBS subtypes. As this was a pilot study, the data collected was preliminary and limited by a small sample size. Future larger scale studies on proteomic profiling can potentially help with understanding the immune dysregulatory mechanisms driving IBS, and guide the diagnosis of and differentiation between subtypes.

References

[1] Tsigaridas A, Anagnostopoulos AK, Papadopoulou A, Ioakeim S, Vaiopoulou A, Papanikolaou IS, Viazis N, Karamanolis G, Mantzaris GJ, Tsangaris GT, Gazouli M. Identification of serum proteome signature of irritable bowel syndrome: Potential utility of the tool for early diagnosis and patient's stratification. J Proteomics. 2018 Sep 30;188:167-172.
[2] Darkoh C, Comer L, Zewdie G, Harold S, Snyder N, Dupont HL. Chemotactic chemokines are important in the pathogenesis of irritable bowel syndrome. PLoS One. 2014 Mar 25;9(3):e93144.
[3] Moraes L, Magnusson MK, Mavroudis G, Polster A, Jonefjäll B, Törnblom H, Sundin J, Simrén M, Strid H, Öhman L. Systemic Inflammatory Protein Profiles Distinguish Irritable Bowel Syndrome (IBS) and Ulcerative Colitis, Irrespective of Inflammation or IBS-Like Symptoms. Inflamm Bowel Dis. 2020 May 12;26(6):874-884.
[4] Sheikhesmaili F, Jalili A, Taghizadeh E, Fakhari S, Jalili K, Ghaderi E, Rahimi E. The CCL28 levels are elevated in the serum of patients with irritable bowel syndrome and associated with the clinical symptoms. Am J Clin Exp Immunol. 2021 Feb15;10(1):23-29.
[5] Carvalho A, Lu J, Francis JD, Moore RE, Haley KP, Doster RS, Townsend SD, Johnson JG, Damo SM, Gaddy JA. S100A12 in Digestive Diseases and Health: A Scoping Review. Gastroenterol Res Pract. 2020 Feb 26;2020:2868373

Introduction

Food is often reported as a trigger for symptoms in patients with irritable bowel syndrome (IBS). One of the proposed pathophysiological mechanisms is a local immune response to food antigens, triggered by a preceding infection¹.

Aims & Methods

This study aimed to investigate rectal mucosal reactions to food in patients with IBS. Therefore, patients with IBS and food-related symptoms were included. Allergies to the food items that were tested during the colonoscopic antigen provocation (COLAP) were excluded by an allergologist. The COLAP was started in the absence of macroscopic abnormalities during sigmoidoscopy. A 200 μL solution of each food antigen (wheat, gluten, soy, and milk; administered in a randomized order and blinded), a negative control (NaCl 0.9%), and a positive control (histamine) were injected in the rectal mucosa, with a positive reaction defined as mucosal edema 12 minutes after injection and judged based on a previously used semiquantitative scale ². The reaction was independently judged by two endoscopists, resulting in a positive or negative reaction when they agreed and doubtful when they did not.

Results

Data from ten patients were available for this interim analysis. Nine were female, with a median age of 45 [range 24-58] years, and a median IBS symptom severity score of 356 [range 197-416], i.e. in the moderate to severe range. Six patients had predominant constipation, one predominant diarrhea, and three mixed bowel habits. COLAP was positive in seven patients, with a positive reaction for one food antigen in three patients and for two food antigens in four patients. In the other three patients, the test was only doubtful for one of the food antigens (n=2), or negative for all (n=1). A positive reaction to gluten was observed in five patients, to soy in three, to wheat in two, and to milk in one (Table). The reaction to histamine was positive in eight patients, with no positive reaction after injection of the negative control in all.

Conclusion

A local intestinal reaction to food antigens was seen in a subset of patients with IBS. Further research will focus on underlying pathophysiological mechanisms and clinical relevance of these findings.

References

1. Aguilera-Lizarraga J, Florens MV, Viola MF, Jain P, Decraecker L, Appeltans I, et al. Local immune response to food antigens drives meal-induced abdominal pain. Nature. 2021;590(7844):151-6.
2. Bischoff SC, Mayer J, Wedemeyer J, Meier PN, Zeck-Kapp G, Wedi B, et al. Colonoscopic allergen provocation (COLAP): a new diagnostic approach for gastrointestinal food allergy. Gut. 1997;40(6):745-53.

Introduction

A key feature of IBD pathogenesis is response dysregulation of both the innate and adaptive immune system^1,2. Hence specific inflammatory protein profiles may be a promising biomarker approach for diagnosis and personalized therapy in IBD. Serum proteome of IBD, particularly in multi-ethnic Asian patients, remains less defined.

Aims & Methods

We aim to investigate the systemic inflammatory protein profiles in multi-ethnic Asian patients with IBD and compare them to healthy controls.
The study cohort was made up of 92 patients with IBD (50.0% Ulcerative colitis (UC), 43.5% Crohn's disease (CD), 6.5% Unclassified IBD)), and 42 control subjects, who are asymptomatic patients undergoing screening colonoscopy with no endoscopic pathology. Serum protein profiling was performed using the Olink Target 96 Inflammation assay. A partial-least square discriminant analysis was undertaken to identify additional discriminative inflammatory proteins. Univariate t-test analyses, with false discovery rate correction, were also performed to identify proteins unique to either UC or CD.

Results

Participants with IBD were younger (42.0 (±14.7) in UC, 43.2 (±15.1) in CD, p<0.01), with greater representation of South Asian ethnicity (32.5% amongst UC, 19.6% amongst CD, p<0.01) and males (75.0% amongst UC, 69.6% amongst CD, p=0.03), as compared to controls.
We found 18 proteins were differentially abundant amongst IBD patients (p<0.05). Half (n=9) of these inflammatory proteins (AXIN-1, CD8A, CXCL1, EN-RAGE, FGF-23, HGF, IL17A, OSM, TGF-alpha) were elevated in both UC and CD. The other six proteins were elevated only in patients with UC (4E-BP1, CCL11, IL-18R1, IL-20, MMP-10, TRANCE). Of the remaining three, two were less abundant in patients with CD (DNER, SCF) and TNF was elevated only in patients with CD. Of interest, three immunoproteins were differentially abundant in participants with either UC or CD (i.e. CCL11, MMP10, TRANCE).

Table1: List of immunoproteins differentially abundant (p<0.05) in varying IBD subtypes, grouped by their key common molecular functions. *indicates that the immunoprotein of interest to be less abundant compared to controls. ^AXIN1 functions - Activation of protein kinase (GO:0032147), WNT signaling process (GO:0016055). ^#MMP-10 function - extracellular matrix organization (GO:0030198). ^$4E-BP1 function - TOR signaling (GO:0031929). ^@DNER function - Notch receptor processing (GO:0007220).

Conclusion

Our pilot study in a multi-ethnic Asian population found distinctive serum protein profile in IBD patients. While some protein changes were shared in both UC and CD, other changes were specific for either UC or CD, suggesting different disease pathways in these two IBD subtypes. We reaffirmed that inflammatory proteins, such as EN-RAGE³, MMP-10⁴ and OSM⁵, were differentially abundant in IBD, consistent with previous reports in predominantly Caucasian cohorts. Further studies with large sample sizes would be required to validate these biomarkers for IBD activity, and prognosis for biologic therapy response.

References

1. Neurath MF. Cytokines in inflammatory bowel disease. Nat Rev Immunol. 2014 May;14(5):329-42.
2. Mahida YR. The key role of macrophages in the immunopathogenesis of inflammatory bowel disease. Inflamm Bowel Dis. 2000;6:21–33.
3. Foell D, Kucharzik T, Kraft M, et al. Neutrophil derived human S100A12 (EN-RAGE) is strongly expressed during chronic active inflammatory bowel disease. Gut 2003;52:847-853.
4. Fonseca-Camarillo G, Furuzawa-Carballeda J, Martínez-Benitez B, et al. Increased expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and MMP10, MMP23 in inflammatory bowel disease: Cross-sectional study. Scand J Immunol. 2021 Jan;93(1):e12962.
5. Sare Verstockt, Bram Verstockt, Kathleen Machiels, et al. Oncostatin M Is a Biomarker of Diagnosis, Worse Disease Prognosis, and Therapeutic Nonresponse in Inflammatory Bowel Disease. Inflamm Bowel Dis. 2021 Oct 18;27(10):1564-1575.

Introduction

Somatization is defined as a tendency to experience and communicate psychological distress in the form of somatic symptoms. Literature suggests that there is a link between somatization and irritable bowel syndrome (IBS). Nevertheless, the association between clinical symptoms of IBS and somatization, especially in children, remains unclear.

Aims & Methods

54 children aged 6-12 with a verified diagnosis of IBS according to Rome criteria IV were included in the study. The control group consisted of 50 healthy children of the same age and gender. The level of somatization was assessed by the Somatoform Symptom Screening test (SOMS-2J by Rief, W., & Hiller, W.), which was modified for children. The intensity of abdominal pain and dyspeptic symptoms were estimated using a 4-point Likert scale. Data were processed using Microsoft Excel 2016 and analyzed with GraphPad (Prism 5.0). Pearson test was used to assess the correlation between SOMS rate and the intensity of somatic complaints.

Results

The level of somatization was significantly higher in children with IBS in comparison to the control group (p<0.0001). There was no difference in somatization rate in patients according to the predominant bowel habit. A direct correlation between the intensity of abdominal pain and the level of somatization (r=+0.37; p=0.005) was established in children with IBS (Fig.1). On the contrary, the intensity of dyspeptic symptoms was less influenced by the rate of somatization (r=+0,18; p=0,20).

Conclusion

To conclude, children with IBS who had higher rates of somatization were revealed to have a higher intensity of somatic complaints, especially abdominal pain. We suggest that somatization plays an important role in the occurrence of somatic symptoms of IBS. It may be one of the reasons for the low effectiveness of pharmacological treatment of IBS in children.

Introduction

Irritable bowel syndrome (IBS) is a disorder of brain-gut interaction often accompanied by psychiatric and/or somatic comorbidities. Intestinal barrier dysfunction has long been hypothesised to be a key player in IBS pathophysiology. However, it is unknown how psychiatric and somatic comorbidities affect intestinal barrier dysfunction. This study aims to assess intestinal barrier function in a large multicentric cohort of adult IBS patients with and without psychiatric/somatic comorbidities.

Aims & Methods

IBS patients (Rome IV) with (N=197) and without (N=171) comorbidities, and healthy volunteers (N=23), were included in six European hospitals. Intestinal permeability (IP) was assessed in vivo with the lactulose-mannitol-sucralose test (LMS) and ex vivo in colonic biopsies using Ussing chambers. Sugar concentrations in the urine were assessed through HPLC-ELSD and GC-MS. The L/M ratio after 2 hours was used as an estimation of the small intestinal permeability, and the %S excreted and the S/M ratio from 2 to 24 hours, for colonic permeability. Colonic biopsies were collected from 17 controls and 18 IBS patients and mounted in Ussing chambers to measure the paracellular permeability to FITC-dextran (4 kDa).

Results

When compared with healthy controls, L/M ratio did not differ in IBS patients with (p=0.33) or without comorbidities (p=0.44). Moreover, the %S excreted and S/M were not altered in IBS patients with (respectively p=0.3 and p=0.09) and without (p=0.14, p=0.1) comorbidities. Interestingly, when comparing results from IBS patients among recruiting hospitals in different parts of Europe, significant differences were found in L/M ratio (p<0.0001), %S (p<0.0001), and S/M ratio (p<0.0001). Lastly, paracellular permeability assessed ex vivo in colonic biopsies was not different between IBS patients and controls (p=0.46).

Conclusion

These results suggest that psychiatric and somatic comorbidities do not alter small intestinal and colonic permeability in IBS patients. Interestingly, our results highlight a strong variability between IBS patients from different countries, which may be explained by lifestyle, environmental, and genetic factors. Further investigations are needed to better understand these findings.

Disclosure

no conflicts of interest

Introduction

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction affecting 5 to 10% of the population, combining chronic abdominal pain and altered bowel transit. Its varied and complex mechanisms make management difficult and can be responsible for impaired quality of life. Patient education is recommended for managing chronic diseases. As part of a patient education program, the first step is to assess patients' knowledge and needs by conducting a shared educational assessment. Experiments conducted in various countries have shown that therapeutic patient education (TPE) can be effective, reducing severity, improving quality of life, and reducing care seeking. These studies have also shown that patients often have a lack of knowledge and/or misconceptions about IBS (1).

Aims & Methods

This study aimed to assess the baseline knowledge level of patients enrolled in a patient education program. Patients with IBS were selected for participation in a TPE program following a multidisciplinary day hospital for IBS. All patients had to have seen a general practitioner and/or a gastroenterologist outside the team without sufficient improvement in their condition. The TPE was based on a document developed in collaboration with a patient organisation (APSSII). This program was divided into five 1-hour sessions (training and discussion time) conducted by different professionals (neurogastroenterologists, clinical psychologist, dietitian) covering the following points:
1) understanding my illness (epidemiology, diagnosis, mechanisms),
2) talking about my illness and expressing my needs (interaction with loved ones, work, doctor, school, rights and support);
3) organizing my daily life, improving my quality of life (impact of IBS on QoL, work, exercise, intimate life);
4) taking advantage of different treatments and care options (placebo, adverse effects, symptomatic and long-term treatment, alternative treatments);
5) the role of eating and diets (balanced diet, lactose-free, gluten-free, low-FODMAP, food allergies, risks of diets). Before the start of each session, questionnaires testing participants' knowledge on the session topic were completed.

Results

From November 2023 to September 2024, 135 questionnaires completed by 43 patients with IBS were included. 70% were women, mean age 45 ± 18 years, subtypes based on IBS transit: IBS-C 55%, IBS-D 33%, IBS-M 12%, with a mean severity (IBS-SSS) of 331 ± 72 points, EQ5D health score of 50 ± 21. Among the most common misconceptions, 25% believed that a diagnosis by endoscopy was possible, 48% believed the disease could be complicated by IBD, and 13% by colon cancer. Regarding treatments, 11% of patients believed that the placebo effect only concerned medications, 58% believed that faecal microbiota transplantation could currently be offered in clinical routine for IBS care, 78% believed that hypnotherapy was only effective if you believe in it, and 68% believed that multi-strain probiotics were more effective than single-strain ones.

Conclusion

This study, conducted in France on patients with moderate or severe forms of IBS, shows a highly variable level of knowledge about their disease depending on the questions, with some significant misconceptions that need to be addressed. These results justify the implementation of therapeutic education for these patients. A study is underway to verify the improvement in patients' knowledge and the existence of a positive impact of this strategy on symptom severity and quality of life.

References

(1) Halpert et al. What Patients Know About Irritable Bowel Syndrome (IBS) and What They Would Like to Know. National Survey on Patient Educational Needs in IBS and Development and Validation of the Patient Educational Needs Questionnaire (PEQ). Am J Gastroenterol 2007; 102:1972-82.

Disclosure

Nothing to disclose

Introduction

Previous studies indicate that patients with irritable bowel syndrome (IBS) may present with altered fecal microbiota and metabolite profiles. While changes in bowel habits seem to not influence the microbiota dynamics, the stability of fecal metabolites in IBS patients has not been addressed yet.

Aims & Methods

This study aimed to assess the stability of the fecal metabolite profile over time, and its link with fluctuations of stool consistency. It used fecal samples from two cohorts (A and B) comprising healthy subjects and patients with IBS diagnosed according to either Rome III (Cohort A) or Rome IV (Cohort B) and subtyped using the Bristol Stool Form (BSF) scale. Cohort A collected fecal samples for 5 consecutive days that were analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). Additionally, IBS patients collected up to 3 additional samples within one of those days. Cohort B collected fecal samples at week 0 (healthy and IBS) and week 4 (only IBS), later analyzed by liquid chromatography-MS (LC-MS). All participants reported stool consistency using BSF scale. Metabolome variation based on the metabolite intensity signals was assessed by Bray-Curtis dissimilarity in R (version 4.2.1). Additional statistical analyses were conducted in GraphPad (version 9.4.1).

Results

Cohort A (7 healthy subjects and 8 IBS patients with mixed bowel habits, IBS-M) provided 66 fecal samples. Twenty-nine samples were collected from Cohort B (7 healthy subjects, 3 IBS-M, and 8 IBS patients with predominant diarrhea). The metabolome of Cohort A (n=155 spectral features) at day 1 showed similar composition with a tendency towards a higher Bray-Curtis dissimilarity in the IBS group (0.026 (0.023-0.028) vs 0.028(0.025-0.032); p=0.10). Over a period of 5 days, metabolome dissimilarities were higher between- than within- individuals (Table 1) and fluctuated minimally over time for both healthy subjects and IBS patients. The stool type however changed more over time in the IBS than the healthy group (p<0.001). Consecutive samples taken within the same day showed higher compositional variance between- than within- IBS patients (Table 1). At individual level, the metabolomic profiles remained stable despite changes in the BSF score. In Cohort B, the metabolome profile comprised 6 999 spectral features. The metabolome dissimilarity was higher in IBS patients as compared to healthy subjects at week 0 (0.045(0.040-0.048) vs 0.048(0.042-0.054); p<0.05). In the IBS group, the metabolome was stable between week 0 and week 4 regardless of stool form and differed more between- than within-patients (Table 1).

Conclusion

The metabolite profile of fecal samples remains stable over time within an individual IBS patient independently of the variation in stool consistency. This study suggests the use of fecal metabolites as a potential non-invasive diagnostic tool in IBS.